Is the EDCS intended to be a tool for the
set-up and exchange of real-world geo data, or is it focused on simulation
with synthetic data?

Certainly the focus of EDCS is on meeting the needs of the modeling
and simulation (M&S) community worldwide. However, there is very little
regarding environmental data concepts that are unique to the M&S community.
For example the meaning of "synthetic", when used by the M&S
community, is "put together" or "integrated". The requirement
of the M&S community is to be able to simultaneously and consistently
represent information about the world in all environmental domains (e.g.,
land, sea, air, and space), not in a manner that has been "balkanized"
along the lines of traditional disciplines (e.g., land maps vs. ocean charts
vs. weather charts).

It is important to remember that much, and perhaps most, environmental
data is not measured, but is generated (modeled) by simulations. Very little
weather data in your daily weather report is measured at observing stations.
But rather, the vast majority of weather data is calculated by complex
models and simulations. The same is true for ocean and space data. Terrain
data is somewhat unique in that it is much more slowly changing, and historically
is thought of as permanent on human-scale time periods. But simulations
have a role there as well; for example, the most common representation
of the geometry of the surface of the terrain is as a grid of elevation
values. But then, what is the "real" elevation spatially between
the grid points? Traditionally it is modeled using assumptions about topography
as a bilinear interpolation, nearest-neighbor, or spline-fit "approximation".
The data we have captured from the "real world" serves merely
as boundary conditions for a model that predicts the terrain elevation,
everywhere. Is the result "real"? No. Is the result simulation
data? Technically, yes, although we all agree to accept the fiction that
it is "real".

There is no real distinction between concepts about "the world"
used in models and simulations, and concepts about the "the world"
used in "the real world". The only difference is the fidelity
of the data values associated with those concepts. In many cases, we treat
the values of those concepts, when generated by models, as "reality"
(as best we can know it) -- for example, the weather or the topography
of the terrain. In some cases, yes, models and simulations may be executed
(or maps prepared) with totally fictitious data values. That is done every
day in the weather community when predictions about future events are generated.
It is a common misunderstanding to characterize M&S data as "fake",
and all other data as "real". The actual distinctions are much
richer and nuanced.

SEDRIS (and EDCS in particular) are used by tools that enable import
of products generated by the geo-data community into M&S systems. Import
of information from such product datasets is an important element in the
creation of M&S databases. But it is also true that M&S databases
are already generated, and promulgated, in the "real world" and
treated as "real" -- the weather example. SEDRIS technologies,
therefore, do not recognize a false distinction between M&S-centric
perspectives and non-M&S-centric perspectives. It is intended that
there be one set of integrated environmental concepts and, eventually,
integrated environmental data characterized by those concepts regardless
of the source or destination of the data. The fact that this work springs
from the M&S community may be regarded as an accident of history, and
should not be regarded as having deeper meaning.

Is the EDCS intended as
a replacement for specialized coding catalogues or formats developed by
DIGEST, IHO, WMO, ICAO, etc., and is it intended to replace the use of
codes from those catalogues in products produced by various sources including
national and military mapping agencies?

Specialized coding catalogues or formats have restricted scope, overlap,
gaps, and inconsistencies. The EDCS is intended to bring together selected
concepts from those specialized catalogues or formats into a common framework
so that many communities can both understand each other and use a single
set of common concepts that "know no bounds". That set of common
concepts can then serve as a basis for meaningful, unambiguous data interchange.

SEDRIS (as a whole) provides mechanisms needed to exchange data sets
amongst modeling and simulation (M&S) programs and to import to and
export from such M&S systems. But it also provides mechanisms to exchange
data sets with "any" application interested in environmental
data. While there is no intent to specifically supplant existing data interchange
mechanisms where they meet customer requirements (e.g., DIGEST VRF), the
SEDRIS technologies intentionally address emerging requirements for an
integrated perspective on the environment, and provide an integrated mechanism
for representing and exchanging integrated environmental data. Existing
mechanisms (specialized catalogues or formats) do not fulfill that requirement.
While it happens that M&S systems are the first category of applications
to recognize this requirement, we believe that other categories of applications
will recognize this emerging requirement in the future, and embrace the
SEDRIS technologies where they apply.